Abstract
We used local violations of regularities within visual images and with a low calculated salience to test whether pop-out is different from salience. In line with this, lowly salient violations of the overall image pattern attracted the eyes and attention. We used patterns consisting of tiles, either forming a fully regular pattern, or a locally irregular pattern. Within a visual search task, in half of the trials one of the tiles stood out because it was rotated so as to violate the overall regularity (here: of point symmetry at 16 locations). Although this pop-out tile was anti-predictive for the target location (i.e. never at the target position), we found that participants significantly more often fixated on this image position than on every other location, and the mere presence of the rule violation (i.e. the rotated tile) slowed down correct target detection. In Experiment 1 (N=38), we also varied the local feature salience of each tile relative to its surround, and found this was without additional effect on attraction of the eyes and attention by the rule violation. We also found a facilitation effect when the target was located at the same position as the rule violation (Exp. 2, N= 16), and results could be replicated with photographs of natural scenes (Exp.3, N = 16). Our results point to rule violations as one major origin of attentional attraction by pop-out stimuli.
Meeting abstract presented at VSS 2012